Help! I laugh too easily and can’t stop being isekai’d!

Roku Zaregoto lived like your typical serious Japanese student for one reason— to become a respected ambassador in America! While his classmates went to karaoke, onsens, festivals, beaches, shops, and all the localities of Japanese youth, Roku studied English. To become an ambassador, Roku needed to learn English! So, Roku burned through his school years just to speak fluent English. Halfway through his final year of high school, a foreign exchange student arrived. Roku immediately talked to them, but Roku didn’t know his first casual conversation would lead to him being isekai’d! This was the start of a series of isekais because Roku laughed too easily! The original ideas came from reddit comments by datinggoskrrrrrrrrra, Hobomanchild, Luhood, lieferung, raoul_d, and DustyLance. I also used VarysIsAMermaid69’s Garbage Isekai Bingo Board. Thank you, redditors, for the inspiration and guidance!